Maize regulatory gene opaque-2 encodes a protein with a "leucine-zipper" motif that binds to zein DNA.
The opaque-2 locus (o2) in maize regulates the expression of many members of the zein multigene family of storage proteins. cDNA clones for a wild-type allele of the (o2) locus (O2) were isolated from a maize endosperm cDNA library and sequenced. We found a 258-nucleotide 5' leader sequence containing three short open reading frames followed by a sequence specifying a protein of 437 amino acids. The presumptive amino acid sequence of the protein (O2) specified by the O2 cDNA contains a "leucine-zipper" domain characteristic of some mammalian and fungal transcription activation factors. lacZ-O2 fusion constructs, using nearly the entire coding region of O2 or only a fragment specifying the leucine-zipper domain, were expressed in Escherichia coli. In an in vitro binding assay, the beta-galactosidase-O2 fusion proteins bound to two specific regions on the 5' side of the coding sequence in a zein genomic clone. This suggests that the O2 protein affects zein transcription through direct interaction with one or more zein promoter elements.
Schmidt
R J
RJ
Department of Biology, University of California, San Diego, La Jolla 92093.
Burr
F A
FA
Aukerman
M J
MJ
Burr
B
B
D000595:Amino Acid Sequence; D001483:Base Sequence; D015139:Blotting, Southern; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D005796:Genes; D005809:Genes, Regulator; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D010944:Plants / Q000235:genetics*; D011993:Recombinant Fusion Proteins / Q000302:isolation & purification / Q000378:metabolism; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D003313:Zea mays / Q000235:genetics; D015028:Zein / Q000235:genetics*
D004268:DNA-Binding Proteins; D011993:Recombinant Fusion Proteins; D004247:DNA; D015028:Zein